Differential pressure measuring probe with bottoming indicator

Abstract

A bottoming indication system indicates contact between an inner wall of a fluid conducting conduit and a tip of a differential pressure measuring probe. The system includes a piezoelectric device and an indicator. The piezoelectric device is affixed to the tip of the differential pressure measuring probe so that pressure exerted on the piezoelectric device by contact between the piezoelectric device and the inner wall of the conduit produces a voltage difference across the piezoelectric device. The indicator is in electrical communication with the piezoelectric device so that a voltage difference across the piezoelectric device activates the indicator to indicate contact between the inner wall of the conduit and the tip of the differential pressure measuring probe.

1. A bottoming indication system for indicating contact between an inner wall of a fluid conducting conduit and a tip of a differential pressure measuring probe, the system comprising:
 a piezoelectric device affixed to the tip of the differential pressure measuring probe wherein pressure exerted on the piezoelectric device by contact between the piezoelectric device and the inner wall of the conduit produces a voltage difference across the piezoelectric device; 
 an indicator in electrical communication with the piezoelectric device wherein a voltage difference across the piezoelectric device activates the indicator to indicate contact between the inner wall of the conduit and the tip of the differential pressure measuring probe. 
 
   
   
     2. The system of  claim 1  wherein the piezoelectric device includes a piezo film sensor element. 
   
   
     3. The system of  claim 1  wherein the piezoelectric device includes a piezoresistive pressure sensor. 
   
   
     4. The system of  claim 1  wherein the indicator includes a visual indicator. 
   
   
     5. The system of  claim 1  wherein the indicator includes an audible indicator. 
   
   
     6. The system of  claim 1  further including a power supply in electrical communication with the piezoelectric device for supplying electrical power to the piezoelectric device. 
   
   
     7. The system of  claim 1  further including an electrical signal amplifier in electrical communication between the indicator and the piezoelectric device. 
   
   
     8. The system of  claim 5  further including a power supply in electrical communication with the electrical signal amplifier for supplying electrical power to the electrical signal amplifier. 
   
   
     9. The system of  claim 1  further including electrical conductors for providing the electrical communication between the piezoelectric device and the indicator. 
   
   
     10. The system of  claim 9  wherein the differential pressure measuring probe further includes:
 an elongated body having upstream and downstream faces; 
 at least first and second fluid carrying plenums within the body; 
 a longitudinal passage within the body; 
 at least one opening in the upstream face of the body, each opening in fluid communication with the first fluid conducting plenum; 
 at least one opening in the downstream aspect of the body, each opening in fluid communication with the second fluid conducting plenum; and 
 wherein the electrical conductors are disposed in the longitudinal passage. 
 
   
   
     11. A differential pressure measuring probe for insertion into a fluid conducting conduit having an inner wall, the probe comprising:
 an elongated body having upstream and downstream faces and a tip; 
 at least first and second fluid carrying plenums within the body; 
 at least one opening in the upstream face of the body, each opening in fluid communication with the first fluid conducting plenum; 
 at least one opening in the downstream aspect of the body, each opening in fluid communication with the second fluid conducting plenum; 
 a piezoelectric device affixed to the tip of the body wherein pressure exerted on the piezoelectric device by contact between the piezoelectric device and the inner wall of the conduit produces a voltage difference across the piezoelectric device; 
 an indicator in electrical communication with the piezoelectric device wherein a voltage difference across the piezoelectric device activates the indicator to indicate contact between the inner wall of the conduit and the tip of the differential pressure measuring probe. 
 
   
   
     12. The system of  claim 11  wherein the piezoelectric device includes a piezo film sensor element. 
   
   
     13. The system of  claim 11  wherein the piezoelectric device includes a piezoresistive pressure sensor. 
   
   
     14. The system of  claim 11  wherein the indicator includes a visual indicator. 
   
   
     15. The system of  claim 11  wherein the indicator includes an audible indicator. 
   
   
     16. The system of  claim 11  further including a power supply in electrical communication with the piezoelectric device for supplying electrical power to the piezoelectric device. 
   
   
     17. The system of  claim 11  further including an electrical signal amplifier in electrical communication between the indicator and the piezoelectric device. 
   
   
     18. The system of  claim 11  further including a power supply in electrical communication with the electrical signal amplifier for supplying electrical power to the electrical signal amplifier. 
   
   
     19. The system of  claim 11  further including electrical conductors for providing the electrical communication between the piezoelectric device and the indicator. 
   
   
     20. The system of  claim 19  wherein the body further includes a longitudinal passage within the body and wherein the electrical conductors are disposed in the longitudinal passage.